Furnace won’t start in Boise — what to check first

First cold snap of the season hits the Treasure Valley and the furnace does nothing. Before you start Googling parts or cracking the cabinet, run through a few safe checks. This is not a diagnosis guarantee — it’s the stuff that often saves a truck roll, and the line where you should stop and call.

1. Thermostat basics

• Set to Heat (not Off / Cool / Emergency Heat unless you know you need it).
• Set the temperature a few degrees above the room reading.
• If it’s battery-powered, weak batteries can make the display look fine while the call for heat fails — fresh batteries are cheap insurance.

2. Power to the furnace

• Confirm the furnace switch (looks like a light switch near the unit) is On.
• Check the breaker labeled furnace / air handler — if it’s tripped, reset once. If it trips again, stop and call.

3. Filter and airflow

A clogged filter can cause a furnace to overheat and shut down on a limit switch. Pull the filter and hold it to a light — if you can’t see through it, replace it with the correct size. Don’t run long without a filter.

4. What I look for when I arrive

On a no-heat call I start with safety, then ignition, flame sensing, inducer / pressure switches, blower, filter restriction, and thermostat setup. You’ll get a clear explanation and an upfront price before work starts — same standard as any other job.

When to call Jeff

If those checks don’t bring heat back — or you’re not comfortable doing them — call (208) 210-6141. No-heat gets priority; same-day when possible. Serving Boise, Meridian, Eagle, Nampa, Kuna, Star, Garden City, and Caldwell. Hours 7:00 AM–8:00 PM, Mon–Sun.

Related: Help — No heat · Furnace repair · Before you call